I had no question over the caliber, just the name/model.
The RN bullet came first but they wouldn't have been made by Remington originally.
Scroll down to military use/military ammo on the link below:
https://en.wikipedia.org/wiki/7%C3%9757mm_Mauser
Here is some old UMC ammo on GB if interested. The seller has more than one listing on these:
https://www.gunbroker.com/item/859186976
https://www.gunbroker.com/All/search...Sellers=183669